UNITED STATE S E N VIRONMENTA L PRO TE CTION AG EN C Y WASHINGTON, D.C. 20460

MEMORANDUM
Date: September 4, 2014 

### OFFICE OF CHEMICAL SAFETY AND 

### POLLUTI ON PREVENTIO N

SUBJECT: MCPB. Response to Comments Received Regarding Seeping Document in Support of Re gis trat ion Review

PC Code: 019201,0 1 9202 Decision No.: 491965 Petition No.: Not Appl icabl e Risk Assessment Type: Single Chemical T XR No.: Not Applicable MRID No.: None

FROM: Alexandra LaMay, Biologist DP Barcode: 0420784 Registration No.: Not Applicable Regulatory Action: Registration Review Case No.: NA CAS No.: 94-81-5 40 CFR: §180

. 318

Danette Drew , Chem i st**-:::-~-...**

THRU: Linda Taylor, Toxicologis Risk Assessment Branch VII Health Effects Division (7509P) Office of Pe sticide Programs
Michael Metzger, Chief, Risk Assessment Branch VII Heal th Effects Division (7509P) Office of Pesticide Programs
TO: Khue Nguyen Pesticide Re

- evaluation Division (7508P) Office of Pesticide Programs

Attached is the Health Effects Division's (HED) response to comments received regarding the human health seepi ng document for MCPB to support the registration review process.

Page 1 of 4Task Force Comments Regarding MCPB Human Health Assessment Scoping Document:

Task Force Comment: The MCPB Task Force believes the request for additional pea field trial data has been made without consideration of data submitted January 29 , 1999 by the Interregional Research Project No .4 ( IR4 ). MRID 44754101 Corley, Johannes and Kunkel, Daniel (1999) MC PB : Magnitude ofthe Residue on Pea, Unpublished study prepared by IR4. 423 p. This study provides MCPB and metabolite residue data from eight re s idue trials conducted in typical pea producing areas of the US , EPA Regions 1 , 5 , 10 , 11 and 12. Residue data included in this study covers Succulent Peas with Pods, Succulent Peas without Pods and Dried Peas. The MCPB Task Force belie ves the data from this report i s suffic ient to support the continued registration of MCPB on peas and reference to additional pea field trial data identified in multiple places is no t accurate.
HED Response: Under registration review, HED will perform a full evaluation of the January 1999 pea field tri al study (MRID 44754101; submitted in response to a S eptember 21, 1993 Data-Call In notice) for scientific acceptability and will determine if the study fulfills the outstanding MCPB data requirement for pea field trial data. A preliminary screen of the data indicates that the study is scientifically acceptable and appears to meet th e 860. 1500 guideline
recom mendations
. There is adequate method validation and concurrent storage stability data. The application rate and timing match the current labels for pea use. The tot al number of field trial s (8) and geographical representation (Regions 1, 5 , 10, 11 and 12) are adequate. Although the 860 guideline recommends four of the field trials be done in Region 5 , only two were performed in this region. However , since there is adequate geographical representation overall and all samples (except one just above LOQ ) in all the field trial s had nondetectable ( <0.01 ppm) residues of MCPB and MCPA , additional field trials in thi s region are not needed. MRID 44754101 appear s to fulfill the MCPB DCI requirement for pea field trial data (GDCI- 0 1920 1-16904). Task Fo rce Comment: Whether for a spring planted crop or a fall planted crop , weed control applications with MCPB are made at early stages of pea and mint growth. Post-application activi ties are not generally expected because the preplant through early postemergence period is the timing for application of most available herbicides rather than for hand labor activities. Also , herbicide applications are primarily directed to the soil or weeds rather than to the crop plant as might be targeted for , e.g. , insecticides or fungicides. Therefore, a DFR st udy on MC PB does not appear to be indicated by cropping practices. Early reentry is covered by PPE under the WPS Agricultural Use Requirements. HED Response: The app licati ons on th e label involve foliar applications to crops (i.e., postemergent appl icat ion mint and peas); therefore, post-application exposure i s possible for workers entering treated fields. Even if only early season activities such as irrigation are assessed for workers in treated fields , MOEs are still les s than 2X the LOC of 100. Therefore, DFR data are required for MCPB.
Since the seeping docume nt was completed in January 2014 , the DFR data requirement screening language has been updated. See below.

Page 2 of 4In accordance with 40CFR 1 58, DFR data are requ ired for all occupational (e.g. , crop, nursery, greenhouse use sites) or residential (e.g., ornamental and vegetable gardens , pick your own farms, retail tree farms) uses that could result in post-application exposure to foliage. In the ab se nce of chemical-specific DFR data, EPA uses default values. The 2012 Stand ard Operating Procedures fo r Residential Pesticide Exposure Assessment includes an ana lysis of a numb er of DFR studie s, whic h r esu lted in the selection of a revised def aul t values for the fractio n of the application r ate available for transfer after a foliar app li cation 

### (FAR). These values are based on an analysis of 19 DFR studies. Si n ce that time , the Agricultural Re-entry Task Fo rce has s ubmitted information (MRID 49299201) that corrects an application rate erro r made in the original submission of " ARF039

- Det ermination of Dermal and Inhalation Exposure to Reentry Workers During Chrysanthemum Pinchi n g in a Greenhouse" (EPA MRID 45344501)

. As a result , the ran ge ofF AR val ues was revised from 2%

- 89% to 2%

- 47%. [n the data, a large range of transferability is observe d and thi s variabi lity can potentially be attribu tab le to many facto r s such as active ingredient; formulation; fie ld co nditions in th e studies; weather conditions (e.g., humidity); or many other difficult to quantify facto r s
. A lth ough witnessed ac ross multiple chemicals, this range in FAR values is not expected when considering DFR data for a s in gle chemical. At this time , the ARTF submission did not alter the selection of 25 % as the reasonable, high-end default value. Because DFR data are no t available for MCPB , EPA is using the defau lt value of 25 %

. Although there may be a small degree of uncertainty in the use of the default DFR valu e for MCPB (i

.e., there is a small chance that the FAR value may exceed the applicable default va lue), it i s likely that the health-p rotective asp ects of EPA's occupational post-application assessment methodology will more than compensate for thi s p oten tial uncertainty. For example, when assessing res idential and occupational post-application exposure to gard ens and ornamenta ls , EPA assumes the follow in g: exposures occur to zero-day (i.e. , day of application ) residues every day of the assessed exposure duration (i.e., EPA assumes that no dissi p ati on or degradation occurs , it doesn't rain, etc); individuals perform the same postapplication ac tivities p er formed in the t r ansfer coefficient study day after day (e.g., weeding, harvesting, pruning , etc.); and individuals engage in these post-application activities for a highend amount of time every day (represented by data reflecting time spent garde ning based on survey data).
Given the con servati sms disc u ssed above and the potential compounding nature of these conserva tisms, EPA is able to rely upon the calcu lated exposure es ti mates w ith confiden ce th at exposure is not being underestimated.
Since the highest estimated occupational post-app li cation exposure using default DFR values for MCPB is not minimal in compariso n to the level of concern (i.e., the calculated MOE is not greater than 2 times higher than the level of concern , MOE < 200 compared to the LOC of I 00); EPA i s requirin g th e 40CFR DFR data. Therefore, EPA is requiring the 40CFR DFR data requirement to facilitate any necessary expo sure assessments re fin eme nts and to furthe r EPA's general und e rs t a nd in g of the availability of d i slodgeable foliar pesticide residues.

Task 

### Force Comment: Due to recent and ongoing activities, Canadian and Codex MRLs should be reviewed again before the concl u sion of Registration Review. H armonization and trade irritant consi deratio n s may be applicable.

Pag e 3 of4HED Response: HED is not aware of any current international MRLs for MCPB but would be grateful for any informati on that the Task Force could provide on " recent and ongo in g activities " regardi ng MCPB. If Codex , Canadian or Mexican MRLs are estab li shed for MCPB during the registration re view process, the EPA will consider any harmoni zation i ssues wi th U.S. tolerance levels.

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